1. Field of the Invention
The present invention relates to a cap with a valve unit attached thereto which may be used as a fuel cap for use in an automotive vehicle or the like, and more particularly to a cap with a valve unit of the type which releases negative pressure in a fuel storage tank.
2. Description of the Prior Art
A fuel cap for use in an automotive vehicle is generally provided with a valve adapted to release negative pressure in a fuel storage tank. Heretofore, this kind of fuel cap with a negative pressure release valve includes a hollow body portion 1 which is threadably secured to a fuel injection hole 7 and a valve body 2 disposed against a valve hole 6 formed at the upper portion of the valve body 1 as shown in FIG. 1. In this fuel cap, the valve body 2 of relatively large size, a retainer plate 3 adapted to retain the valve body 2 thereon, a coil spring 4 adapted to urge the valve body 2 in such a direction that the valve body 2 is closed, and a spring retainer plate 5 are all incorporated in the body portion 1. It is requested, therefore, that a valve unit including the valve body 2 and the coil spring 4 be formed into a smaller size. There has been developed a fuel cap with a smaller valve unit.
However, while the dimensions of a valve unit are reduced, operability in the couse of assembly will deteriorate on the ground that a comparatively small valve body and a retainer plate need be properly positioned in the cap one after the other, Furthermore, such valve body and coil spring may be assembled in an improper position.